measurement systems and applications mariolino de cecco antonio selmo michele confalonieri
DESCRIPTION
Measurement Systems and Applications Mariolino De Cecco Antonio Selmo Michele Confalonieri. Force Panel. The instrument employed. How its electronics work? [ Antonio Selmo ]. Design and purpose of the FP [ a couple of frontal lessons ]. Measurements for Diagnostics - PowerPoint PPT PresentationTRANSCRIPT
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Measurement Systems and Applications
Mariolino De CeccoAntonio Selmo
Michele Confalonieri
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Force Panel
The instrument employed
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
How its electronics work?[Antonio Selmo]
How its electronics work?[Antonio Selmo]
Design and purpose of the FP
[a couple of frontal lessons]
Design and purpose of the FP
[a couple of frontal lessons]
Measurements for Diagnostics
[study and identification of the HTF]
Measurements for Diagnostics
[study and identification of the HTF]
Principles of human diagnosis and rehabilitation
[doct Guandalini and Tomasi]
Principles of human diagnosis and rehabilitation
[doct Guandalini and Tomasi]
Achronims:Fprce Panel – FPHuman Transfer Function - HTF
Logic of the Course
Rehabilitation and its quantification (measure of indexes of performance)
[development of serious games with processing]
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Application: identification of human transfer function for
dexterity assessment and serious games for
rehabilitation
Method: - study of touch technology
- study of signal analog elaboration and conversion- acquisition of human data
- signal processing
Course:- frontal lessons (few)
- exercitation with matlab- building of the application
with Processing- visit to a clinic
Exam:- oral discussion
- homework
Material of the course can be found at http://www.miro.ing.unitn.it
Organization and final examination
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
VERITAS Project
• Project number: 247765• Project acronym: VERITAS• Project full title: Virtual and Augmented Environments
and Realistic User Interactions To achieve Embedded Accessibility DesignS
• Site: http://www.veritas-project.eu/• Starting date: 1 January 2010• Duration: 48 Months
VERITAS is an Integrated Project (IP) within the 7th Framework Programme, Theme FP7-ICT-2009.7.2, Accessible and Assistive ICT
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Design and purpose of the FP - VERITAS Project
Virtual and Augmented Environments and Realistic User Interactions To achieve Embedded Accessibility DesignS
Method
SP1: development of virtual users
SP2: development of the simulation platform
SP3: validation
OBJECTIVE develop virtual humans for accessibility design in virtual simulation of ICT and non ICT products
UNITN activities
Modeling
Measurement
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
• Systems developed:– Garment based Motion
Capture: Ga-MoCap
– Multi-axis load cell
– Force Panel
VERITAS Project - measurement systems developed
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
• Diagnostics by human dexterity estimation• Requirements:
– Measure position of the touch– Measure the applied force– Store the above for path and trajectories– Accuracy and sampling frequency able to reveal
human dexterity– Visual feedback
Idea: “Force Panel”– Display LCD– Touch panel– Force transducers
Design and purpose of the FP - requirements
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Stato dell’arteTouch screen
LCD and cameras
Graph tablets
Design and purpose of the FP - state of the art
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Stato dell’artejoystick Aptics devices and virtual
reality
Design and purpose of the FP - state of the art
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Force Panel
Design and purpose of the FP - Design
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Schema della struttura(disposizione dei vincoli)
Horizontal use Vertical use
= perpendicular to LCD= parallel to LCD
3 load cells
Design and purpose of the FP - Design
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Tipologie di vincolo considerate– Spherical joints– wires
– wires
2 solutions !
Design and purpose of the FP - Design
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Design and purpose of the FP - Design
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Variante con teste a snodo
mechanical design: spherical joint
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
mechanical design: wires
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
mechanical design: wires constraints
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
mechanical design: wires constraints
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Requirements:• No buckling• No finger force through the blues• Diameter 1 mm
Wires with load cell– Length 10 mm (due to physical constraints)
wires– Length 30 mm (FEM analysis → finger force < 0.3 %)
F
mechanical design: wires length
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Lunghezza dei filihorizontal Vertical
Worst case for buckling Worst case for force leakage
mechanical design: wires length
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
• Critical length ≈ 65 mm• Force lost:
• Moments ≈ 10-3 – 10-6 Nm
Caso Errore lettura forza [%]
Worst case horizontal, l = 10 mm 2.41
Worst case vertical, l = 10 mm 2.50
Worst case for buckling, l = 10 mm 5.32
Worst case for buckling, l = 20 mm 0.73
Worst case for buckling, l = 30 mm 0.22
Worst case for buckling, l = 30 mm, e = 0.5 mm 0.23
Worst case for buckling, l = 30 mm, e = 1 mm 0.27
mechanical design: wires length
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
VGA
Force Conditio
ning
Force Conditio
ning
3 x ANALOG IN
USB
2 x DIGITAL OUT
Touch panel
Force sensors
µController
PC
2 x ANALOG IN
LCD
System design: overall layout
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Touch position measurement circuit
A touch screen is a 2-dimensional sensing device constructed of 2 sheets of material separated slightly by spacers
A common construction is a sheet of glass providing a stable bottom layer and a sheet of Polyethylene (PET) as a flexible top layer
The 2 sheets are coated with a resistive substrate, usually a metal compound called Indium Tin Oxide (ITO). The ITO is thinly and uniformly sputtered onto both the glass and the PET layer
Tiny spacers are placed between the 2 sheets in order to prevent false touch
When the PET film is pressed the two resistive surfaces meet. This position can be read as illustrated in next slides
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Indium tin oxide (ITO, or tin-doped indium oxide) is a solid solution of indium(III) oxide (In2O3) and tin(IV) oxide (SnO2), typically 90% In2O3, 10% SnO2 by weight. It is transparent and colorless in thin layers while in bulk form it is yellowish to grey. In the infrared region of the spectrum it is a metal-like mirror.
Indium tin oxide is one of the most widely used transparent conducting oxides because of its two chief properties:- its electrical conductivity - optical transparency
Touch position measurement circuit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
5 V
GND
VS - sense
€
R0
y
L€
R0
L − y
L
€
R0
x
L+ RT
€
VS = 5R0
yL
R0
yL
+ R0
L − yL
=5
Ly
Ly+
R0 is the total resistance of the substrateRT is the touch resistance
Touch position measurement circuit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Reading the x coordinate is similar
Note that in the equivalent circuit there are capacitive effects that lead to a certain delay that usually is less than 10 ms
Touch position measurement circuit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Electronics scheme
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Alim. cella
Output cella
Alim. condiz. (± 15 V DC)
Circuito di condizionamento
Pre-Amplificazione e Filtro analogico
passa bassoBessel V ordine
Pre-Amplificazione e Filtro analogico
passa bassoBessel V ordine
DC / DCDC / DC
Alimentazione(12 V DC)
Cella di carico
Cella di carico
μCμCShift del segnale
(μC legge solotensioni positive)
Shift del segnale(μC legge solo
tensioni positive)AmplificazioneAmplificazione
Conditioning unit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Conditioning unit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Bessel lowpass 5° order
Gain and offset adjustment: Arduino reads only positive voltages (0 – 5 V)
Full Wheatstone bridge
Conditioning unit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
RISPOSTA TEMPORALE AL GRADINO DEL FILTRO PASSA BASSO DEL 5° ORDINE (Risposta di Bessel con frequenza di taglio 1 kHz)
20s
50s
Tempo di assestamento
No sovraelongation
500 s
Conditioning unit
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
• Arduino UNO
X
Y
F1
F2
F3
Alimentazione lungo XAlimentazione lungo X
Attesa assestamento circuito RCAttesa assestamento circuito RC
Lettura valore XLettura valore X
Alimentazione lungo YAlimentazione lungo Y
Attesa assestamento circuito RCAttesa assestamento circuito RC
Lettura valore YLettura valore Y
Lettura valore F1Lettura valore F1
Lettura valore F2Lettura valore F2
Lettura valore F3Lettura valore F3
PCPC
Inizializzazioni(costanti, variabili e pin μC)
Inizializzazioni(costanti, variabili e pin μC)
sw design: embedded system
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
PIN per lettura XPIN per lettura X
TASK 2 – PC TASK 3 – PC
Ricezione dati ed applicazione modello di
taratura
Ricezione dati ed applicazione modello di
taratura
Gestione delle immagini in
relazione alle risposte di chi sta di fronte al
pannello
Gestione delle immagini in
relazione alle risposte di chi sta di fronte al
pannello
TASK 1 – Arduino
t assest. RCt assest. RC
Read XRead X
PIN per lettura YPIN per lettura Y
Read F1, F2, F3 nel t assest. RCRead F1, F2, F3 nel t assest. RC
Read YRead YInvio dati via RS-232Invio dati via RS-232
0
5
5.1
t [ms]
10.110.2
15.2
25.2
8
2 task paralleli su PC:- uno segue l’Arduino, - uno è indipendente
sw design: task analysis
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Acquisition
• Inizializzazioni• Lettura RS-232• Riconoscimento stringa• Distinzione segnali• Eventuali operazioni di
filtraggio• Operazioni di taratura
Elaboration and graphical output
• Inizializzazioni• Attesa inizio
acquisizione• Calcolo della tara del
sistema• Elaborazione (gestione
delle immagini in relazione all’interazione con l’utente)
sw design: two independent tasks on the PC
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
1. Touch position (resistive touch)
2. Force (load cell)
3. Touch position (load cell)
Calibration
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Force Panel - calibration
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Measurement model:• Linear behaviour on both directions• No interactions
uncoupled modelling
yaym
xaxm
qymy
qxmx
+=+=xm [pixel]
ym [pixel]xm = f (xa)ym = f (ya)xm = f (xa)ym = f (ya)
xa [bit]
ya [bit]
calibration: position
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
• Non-linear behaviour for:– Touch position– Force
€
FT = Fii=1
3
∑
FT [bit]
Fm [N]Fm[N] = f (Fa , xm , ym)Fm[N] = f (Fa , xm , ym)
xm [pixel]
ym [pixel]
€
Fm = a+bxm + cym +dxm2 + exmym + fym
2 + gFT +hFT xm + iFT ym + jFT xmym
calibration: force
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
€
Fm = a+bxm + cym +dxm2 + exmym + fym
2 + gFT +hFT xm + iFT ym + jFT xmym
€
1 xm1 ym1 xm12 ... ... ... ... ... FT1xm1ym1
... ... ... ... ... ... ... ... ... ...
1 xmN ymN xmN2 ... ... ... ... ... FTN xmN ymN
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥⋅
a
b
c
d
e
f
g
h
i
l
⎡
⎣
⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥
=
Fm1
...
FmN
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥
For N measurements made in different positions and with different forces it is possible to build the following linear relation
Than, with a pseudoinverse computation, the 10 coefficients of the polynomial model are estimated
WORK IN CLASS Force Panel - calibration: force
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
€
Fm = a+bxm + cym +dxm2 + exmym + fym
2 + gFT +hFT xm + iFT ym + jFT xmym
€
1 xm1 ym1 xm12 ... ... ... ... ... FT1xm1ym1
... ... ... ... ... ... ... ... ... ...
1 xmN ymN xmN2 ... ... ... ... ... FTN xmN ymN
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥⋅
a
b
c
d
e
f
g
h
i
l
⎡
⎣
⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥
=
Fm1
...
FmN
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥
The pseudoinverse computation gives the 10 coefficients of the polynomial model:
€
A ⋅x = b
€
x = AT ⋅A( )−1AT ⋅b
€
ATA ⋅x = ATb
€
ATA( )−1ATA ⋅x = ATA( )
−1ATb
NOTE: ATA is generally a square and full rank matrix
WORK IN CLASS Force Panel - calibration: force
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
€
Fm = a+bxm + cym +dxm2 + exmym + fym
2 + gFT +hFT xm + iFT ym + jFT xmym
WORK IN CLASS Force Panel - calibration: force
Files given:- read_float.m
How to use read_float :
jj = 1 ; % numero filefile = ['dati_celle_armon_', num2str(jj), '.txt'] ; dati = read_float(file, ',', ':') ;clc
Dati = cell2mat(dati);
% grammi -> NewtonDati(:,1) = Dati(:,1)*(9.81/1000) ;
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
% Data are saved on 9 files “dati_celle_armon_1…9.txt”As follows on columns:% 1 -> calibration load [g]% 2 -> x position [pixel]% 3 -> y position [pixel]% 4 -> load cell 1 (in alto) [N]% 5 -> load cell 2 (in basso a sx) [N]% 6 -> load cell 1 (in basso a dx) [N]% 7 -> load cell sum [N]
WORK IN CLASS Force Panel - calibration: force
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
€
Fm = a+bxm + cym +dxm2 + exmym + fym
2 + gFT +hFT xm + iFT ym + jFT xmym
€
1 xm1 ym1 xm12 ... ... ... ... ... FT1xm1ym1
... ... ... ... ... ... ... ... ... ...
1 xmN ymN xmN2 ... ... ... ... ... FTN xmN ymN
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥⋅
a
b
c
d
e
f
g
h
i
l
⎡
⎣
⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥
−
Fm1
...
FmN
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥=
ε1
...
ε N
⎡
⎣
⎢ ⎢ ⎢
⎤
⎦
⎥ ⎥ ⎥
chi2gof Chi-square goodness-of-fit test on the vector Performs a chi-square goodness-of-fit test for discrete or continuous distributions. The test is performed by grouping the data into bins, calculating the observed and expected counts for those bins, and computing the chi-square test statistic SUM((O-E).^2./E), where O is the observed counts and E is the expected counts. This test statistic has an approximate chi-square distribution when the counts are large.
WORK IN CLASS Force Panel - calibration: force
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
WORK IN CLASS Force Panel - calibration: force
Procedure:
1.With the pseudoinverse computation estimate the 10 coefficients of the proposed polynomial model taking one data file at your choice
2.Apply the estimated coefficients to the model to predict (validate) the model behaviour using a different data file
3.Analyse the residuals and the validation behaviour
4.Apply the chi2gof test to verify the randomness of the residuals
5.Try to choose different mathematical models and see how the chi2gof test performs
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
∑=
=3
1iiT FF
{ }
⎥⎥⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢⎢⎢
⎣
⎡
⎭⎬⎫
⎩⎨⎧
=
yx
yx
yx
yx
yx
Tm
m
Tm
m
Tm
m
Tm
m
Tm
m
Tm
m
Tm
mss
ee
dd
cc
bb
aa
F
F
F
F
F
F
F
F
F
F
F
F
F
Fyx 3121321
1
2 3
F1a [bit]
xm = f (F1a , F2a , F3a)ym = f (F1a , F2a , F3a)xm = f (F1a , F2a , F3a)ym = f (F1a , F2a , F3a)
F2a [bit]
F3a [bit]
xm [pixel]
ym [pixel]
Force Panel – calibration position
M. De Cecco - Lucidi del corso di Measurement Systems and Applications
Resolution Accuracy
Position X [mm] < 0.40 ± 1.80 (al 95%)
Position Y [mm] < 0.30 ± 1.80 (al 95%)
Force [N] < 0.05 ± 0.10 (al 95%)
Time [ms] 10 ± 5
Nail Finger finger horizontal
Yellow: resistive touchBlue: load cell reconstruction
Force Panel – calibration position
M. De Cecco - Lucidi del corso di Measurement Systems and Applications